Molded pallet

ABSTRACT

A molded pallet with ranks of parallel top and bottom cavities which are dimensional counterparts of each other in reverse, each top and bottom cavity having a common side wall and each top and bottom cavity having coplanar end walls.

United States Patent 1191 Lawlor 1 1 MOLDED PALLET [75] Inventor: James.1. Lawlor, Glen Rock, N]. [73 Assignee: P.D.Q. Plastics, Inc., Newark,NJ. 221 Filed: Dec. 29, 1971 [21] Appl. No.: 213,371

[52] Cl. 108/51, 108/53 [51] Int. Cl 865d 19/04 [58] Field of Search108/51, 52, 53, 58

[56] References Cited UNITED STATES PATENTS 3,323,656 6/1967 Weiss et a1.1 211 153 3,628,672 12/1971 Heinz 211/153 3,702,100 v 11/1972.Whartonm, 1. 108/58 1 1 Oct. 2, 1973 FOREIGN PATENTS OR APPLICATIONS11/1967 Great Britain 1. 1011/51 632,823 12/1961 Canada ..108/53 PrimaryExaminerFrancis K. Zugel Assistant Examiner1(enneth J. DornerAt!0rneyN0rman N. Popper et a1.

[57] ABSTRACT A molded pallet with ranks of parallel top and bottomcavities which are dimensional counterparts of each other in reverse,each top and bottom cavity having a common side wall and each top andbottom cavity having coplanar end walls.

5 Claims, 4 Drawing Figures PATENTEDBBT mm INVENTOR JA M E5 J. LAW LORATTOR 1 MOLDED PALLET BACKGROUND OF THE INVENTION 1. Field of InventionThis invention relates generally to molded pallets, and particularly tomolded pallets having freedom from distortion and great strength.

2. Prior Art Plastic materials have great appeal for use in the moldingof pallets because they are strong, are light weight, do not requirerepair and maintenance as wood pallets require, need not therefore befrequently replaced, and are low in cost. The rewards of great strengthare sought by a variety of intricate designs. In DeLuca U.S. Pat. No.3,l40,672 strength and lightness of weight is attained by cross-ribsinterconnecting the legs. In Leitzel U.S. Pat. No. 3,187,691, a varietyof oblique ribs impart strength. In Sullivan U.S. Pat. No. 3,l99,496, avariety of circular frustum legs are used. In Sullivan U.S. Pat. No.3,199,468, the coupling of pallets for extra strength is resorted to.Carlson U.S. Pat. No. 3,359,929 provides concentric squares as the basisfor improving strength. 'Toot U.S. Pat. No. 3,424,1 uses ribs definingrectangles, with radial ribs intersecting. While these various formshave strengthened the pallets beyond the strength achieved by the basicdeck with legs, greater strength, freedom from distortion,'freedom fromcracking-is still sought.

SUMMARY OF THE INVENTION It has been found that a molded pallet of greatstrength can be attained by forming a pallet whose deck has co-equal,opposite, parallel top and bottom cavities arranged in ranks. Thecavities on one side equal in volumetric capacity the cavities on theopposite side. In addition, the top and bottom cavities share end wallswhich extend transversely of the pallet from the top to the bottom ofthe-deck. The walls of the cavities, the floors of the top cavities andthe roofs of the bottom cavities all have the same thickness. Thecavities extend across the top and the bottom of the sheet except forthe provision of deeper cavities defining legs, adjacent cavities havecommon side walls. It has been found that this construction providesgreat strength, freedom from breakage and splintering, flexibility andvirtual indestructibility.

DRAWINGS PREFERRED EMBODIMENT Referring now to the drawings in detail,for optimum strength, the plastic palletis molded of high densitypolyethylene, although other strong plastic materials may be used. Thusit is resistant to manycorrosive chemicals, is resistant to moisture,and relatively free from cracking under stress. ln size 40 X 48 X 6inches, one-fourth inch thick it can'sustain a static load of at least25,000 pounds. It is relatively light weight, in comparison toconventional wooden pallets, so that it can be carried by hand. It canbe designed with any chosen number of legs, so as to permit four-wayentry by a fork truck. Its inherent strength is derived mainly from thepositioning of the ranks of cavities with respect to each other, and thelegs are merely incidental for convenience in handling. The choice ofmaterial makes the pallet suitable for use under a wide range oftemperature conditions. It can thus be steam cleaned to conform to FDA.requirements.

The pallet is molded to have a flat sheet defining a load-bearing deck11. The sheet 11 is provided with a plurality of elongated top cavities13. The margins of these top cavities l3 define the top deck surface 10.The bottom surfaces of the floors 14 of these top cavities 13 define thedeck base 12. The top cavities 13 define between them, correspondinginverted bottom, elongated bottom cavities 15. The top cavities l3 andthe bottom cavities 15 are substantially dimensionally equal. The topdeck surface 10 beside the top cavities 13 define the top surfaces ofthe roofs 16 of the bottom I cavities 15.

The top cavities l3 and the bottom cavities 15 are arranged parallel toeach other in ranks across the pallet.

Transverse end walls 17 serve for both the top and bottom cavities 13,15. These end walls lie in the same general plane, and define ends ofthe ranks of cavities 13, 15, extending transversely across the deck 11.The end walls 17 extend from the top surface 10 to the deck base 12.

Large cavities l8 defining legs are formed in the deck 11 and extendbelow the deck deeper .than the cavities 13. The legs 18 interrupt theranks. Thecavities l3,may be approximately 1.75 inches deep from theupper surface of the deck 11 to the bottom surface of the top cavity 13.The legs 18 are deeper, preferably 6 inches deep from the .top of thedeck to the bottom of the leg 19. Thus the cavities 13 are spaced,aboveasurface upon which the pallet rests, sufficiently for the fork of alift to pass under the deck plate 12. The legs 18 are preferablypositioned three on the longer sideof the pallet with a space betweenthe outerlegs of 30 inches, and the center leg of 8 inches wide leavingtwo ,1 l-inch spaces for the standard fork. The walls of the pallet maybe one-quarter inch thick so as to provide sufficient strength andrigidity.

For accomplishing release from a mold, the top cavities l3, and thebottom cavities 15 have non-parallel walls, i.e., the walls of the topcavities 13 converge downwardly from the top surface 10 and the wallsofthe bottom cavities l5 diverge downwardlyfrom the top surface 10 formingcavities having a truncated triangular cross-section. The top surface ofthe floor l4,

and the bottom surface of the roof 16 have the same area. The altitudesof the top and bottom cavities 13, 15 are equal.

The legs 18 converge downwardly from the top surface 10 providing acapabilityv for nesting. The altitudes of each of the cavities 13, 15are the same.

By virtue of this construction,'the material-of the deck 11 isdistributed so as to locate the centroidal axis 4-4 of thedeck verticalcross-section (at .any'point where the section doesnotcut through a legcavity but only through a plurality of topand bottom cavities),

substantially midway between the top deck surface 10 and the deck base12. In this manner of construction,

great resistance to distortion or deflection of a generally planarobject such as the pallet deck is attained.

l claim:

1. A pallet comprising:

a. a sheet of rigid material,

b. a plurality of separate linear cavities in the top and bottom of thesheet, extending across the sheet substantially the full length thereof,

c. the top and bottom adjacent cavities being dimensional counterpartsof each other in reverse,

d. each top and bottom cavity having a continuous side wall in commonwith each other,

e. a rank of top and bottom equal cavities in parallelism with eachother extending at least partly across the sheet,

f. the material defining the cavities disposed to place the centroidalaxis of the material substantially midway between the top surface andbottom surface of the material defining the cavities,

g. the margin of the top cavities defining a top deck surface, and thebottom surfaces of the floors of the top cavities defining a deck base,h. the top and bottom cavities having generally coplanar end wallsextending from the top deck surface to the bottom surface of the deckbase.

2. A pallet comprising:

a. a device according to claim 1, and

b. deeper cavities in the top of the sheet defining legs.

3. A pallet comprising:

a. the device according to claim 1, and

b. a plurality of ranks of cavities extending at least partly across thesheet.

4. A pallet comprising:

a. the device according to claim 2, and

b. the deeper cavities'in the top of the sheet defining legs, spacedsufficiently far apart to receive a fork of a fork lift between them.

5. A pallet comprising:

a. the device according to claim 1, and

b. the sheet and cavities having the same general wall thickness.

1. A pallet comprising: a. a sheet of rigid material, b. a plurality ofseparate linear cavities in the top and bottom of the sheet, extendingacross the sheet substantially the full length thereof, c. the top andbottom adjacent cavities being dimensional counterparts of each other inreverse, d. each top and bottom cavity having a continuous side wAll incommon with each other, e. a rank of top and bottom equal cavities inparallelism with each other extending at least partly across the sheet,f. the material defining the cavities disposed to place the centroidalaxis of the material substantially midway between the top surface andbottom surface of the material defining the cavities, g. the margin ofthe top cavities defining a top deck surface, and the bottom surfaces ofthe floors of the top cavities defining a deck base, h. the top andbottom cavities having generally coplanar end walls extending from thetop deck surface to the bottom surface of the deck base.
 2. A palletcomprising: a. a device according to claim 1, and b. deeper cavities inthe top of the sheet defining legs.
 3. A pallet comprising: a. thedevice according to claim 1, and b. a plurality of ranks of cavitiesextending at least partly across the sheet.
 4. A pallet comprising: a.the device according to claim 2, and b. the deeper cavities in the topof the sheet defining legs, spaced sufficiently far apart to receive afork of a fork lift between them.
 5. A pallet comprising: a. the deviceaccording to claim 1, and b. the sheet and cavities having the samegeneral wall thickness.